Hydrogen reduction of chromium chlorides: A kinetic investigation

The reduction of single pellets of chromic and chromous chlorides by hydrogen has been studied kinetically. The reaction 2 CrCL 3 + H 2 →2 HCl + 2 CrCl 2 was investigated over the temperature range 475−615°C. The rate controlling factor in the range of 475−493°C. is vaporization of chromic chloride; the activation energy was found to be 67.8 K.cal./mole. Between S10 and 615°C, the reaction rate is evidently controlled by heat and internal mass transfer processes. In this case the apparent activation energy is 16.6 K.cal./mole. Reduction of chromous chloride, CrCl 2 + H 2 → 2 HCl + Cr , was investigated over the temperature range 675−800°C. This reaction is also controlled by heat and mass transfer and involves vaporization of the chromous chloride. The apparent activation energy is 25.5 K.cal./mole.